Epoxy fatty acid methyl ester is a vital plastic additive recognized for its exceptional cold resistance, superior plasticizing performance compared to alternatives like DOA, and ability to absorb HCl gas during processing, thereby acting as a thermal stabilizer with low volatility and good water resistance.

However, traditional synthesis methods involve reacting fatty acid methyl ester with formic acid and hydrogen peroxide under strong acid catalysts like sulfuric acid at 45-65°C for several hours, followed by extensive washing, neutralization steps, and distillation. These approaches suffer from significant drawbacks, including high corrosion risks, complex intermediate processing, excessive waste disposal, and energy-intensive purification, which escalate costs and environmental impact.

To address these challenges, researchers have developed a groundbreaking synthesis process that leverages magnetic catalysts for improved efficiency and sustainability. The innovative method involves mixing fatty acid methyl ester with organic acid (formic or acetic acid, 88-100%) and a magnetic catalyst containing Fe, Ni, or Co in specified ratios. The mixture is heated to 50-70°C, followed by a controlled two-hour drip addition of hydrogen peroxide (25-50%). Post-reaction, the mixture is maintained at temperature for 3-6 hours until the epoxy value reaches at least 3.0. The key advancement lies in applying an external magnetic field to attract and separate the catalyst to the reactor walls, simplifying recovery and enabling reuse. The reaction product is then transferred to a separator, where it settles into layers: the aqueous phase is removed, and the organic phase undergoes neutralization using 1-5% solutions of Ca(OH)2, KOH, or NaOH to achieve a pH of 6.5-7.5, directly forming stable salts that eliminate multiple washing steps. Finally, rapid centrifugation dehydration replaces energy-heavy distillation, yielding high-purity epoxy fatty acid methyl ester with minimal moisture content below 0.3%.

This new approach delivers transformative advantages, starting with a streamlined process that reduces operational complexity and slashes production costs. Crucially, the magnetic catalyst system facilitates easy separation and reuse, cutting waste and conserving resources. Additionally, substituting extensive water washing with direct alkali neutralization integrates salts as stabilizers directly into the product, enhancing product quality while reducing effluent volumes. High-speed centrifugation further minimizes energy consumption and prevents discoloration, as highlighted in demonstration trials. For instance, an example run combined 100g fatty acid methyl ester with 30g formic acid and 1.0g magnetic catalyst, achieving an epoxy value of 3.5 after a five-hour reaction; after magnetic separation, neutralization, and centrifugation, about 108g of product was obtained with low water content. Such efficiency gains underscore the method's potential for scalable industrial adoption.

Overall, this synthesis innovation represents a significant leap forward in plastic additive manufacturing, aligning with green chemistry principles by optimizing resource use, lowering environmental footprints, and enhancing economic viability. Future applications could extend to large-scale production of biomaterials like biodiesel-derived esters, promising broad industry benefits.